1. Field of the Invention
The present invention concerns a system for connecting flexible tubing, piping and similar conduits. In one aspect, the invention relates to a system of couplings, elbows, and other fittings for use with such conduits. In another aspect, it relates to special tools for connecting the fittings with such conduits. The invention has particular application in connecting together lengths of plastic tubing, especially for medical purposes.
2. Description of the Background Art
In the field of medicine, plastic tubing is in common use for various purposes. One such purpose lies in transferring fluids to or from the human body, or directly within the body. Another purpose lies in the operation of prosthetic devices such as penile prostheses. In all such uses, it is generally necessary to use special connectors or fittings to connect lengths of tubing together, to connect tubings to fittings, etc. It is also generally necessary and desirable that the connections be easy to make, that they be made quickly, and that they be reliable. This is especially true when the tubing and connectors are used directly within the human body.
Silicone tubing has found extensive application in this type of service, because of its outstanding compatability with the human body. Silicone tubing, however, must be handled with care. In particular, it has been observed that this type of tubing has a tendency to fail if overstretched or subjected to sharp corners or deformed such that its tensile yield strength is exceeded.
Mechanical couplings and similar fittings are finding increasing use in medicine to connect lengths of tubing. Sutures have also been employed, but sutures in general are less convenient to use than mechanical fittings.
One type of mechanical connector is currently available for use in penile prostheses. The connector consists of a doubly conical, hollow male member and a cylindrical female member which snaps onto the male member. The snapping action is effected by a plurality of inward facing, flexible claws on the female member which slide over and grab a conical, annular, angularly protruding flange on the male member. To connect two pieces of tubing with this particular connector, the two pieces of tubing are connected to opposite ends of a coupling. At each end of the coupling, the end of one piece of tubing is passed through an opening in the female member of the connector and then stretched over the male member until it extends past and around the flange on the male member. When the claws on the female member are pushed over the flange on the male member, the claws spring inwardly and trap the tubing in position between the claws and the flange on the male member. In other words, the female member acts as a clip to lock the tubing against the male member.
While the currently available connector mentioned above offers certain advantages over sutures, it has a potential weakness when used with certain types of tubing such as silicone tubing. Since the tubing is overstretched about the male member it may be subject to failure in tension. This is particularly possible at the angularly protruding flange where the tubing is stretched and bent most severely. Moreover the currently available connector mentioned above may not be amenable with use with reinforced tubing. With tubing having reinforcing strands such as nylon or dacron reinforcing strands, the stretching of the tubing over the male member and the bending that may occur at the angularly protruding flange may cause fiber separation and ultimately tubing failure.
Soft flexible tubing, such as silicone and reinforced silicone tubing, has a tendency to neck inwardly when subjected to axial stretching forces. With the connector system described above, this inwardly necking tends to help the tubing pull loose from the connector.